check param, result, type param of function in redefines-builtin-id r…

…ule (#1023)

* check param, result, type param of function in redefines-builtin-id rule

* combine the if statements

* tiny refactoring to make it more Go idiomatic

---------

Co-authored-by: chavacava <[email protected]>

rule/redefines-builtin-id.go

@@ -145,6 +145,31 @@ func (w *lintRedefinesBuiltinID) Visit(node ast.Node) ast.Visitor {
 		if ok, bt := w.isBuiltIn(id); ok {
 			w.addFailure(n, fmt.Sprintf("redefinition of the built-in %s %s", bt, id))
 		}
+	case *ast.FuncType:
+		var fields []*ast.Field
+		if n.TypeParams != nil {
+			fields = append(fields, n.TypeParams.List...)
+		}
+		if n.Params != nil {
+			fields = append(fields, n.Params.List...)
+		}
+		if n.Results != nil {
+			fields = append(fields, n.Results.List...)
+		}
+		for _, field := range fields {
+			for _, name := range field.Names {
+				obj := name.Obj
+				isTypeOrName := obj != nil && (obj.Kind == ast.Var || obj.Kind == ast.Typ)
+				if !isTypeOrName {
+					continue
+				}
+
+				id := obj.Name
+				if ok, bt := w.isBuiltIn(id); ok {
+					w.addFailure(name, fmt.Sprintf("redefinition of the built-in %s %s", bt, id))
+				}
+			}
+		}
 	case *ast.AssignStmt:
 		for _, e := range n.Lhs {
 			id, ok := e.(*ast.Ident)

testdata/redefines-builtin-id.go

@@ -41,3 +41,14 @@ func foo() {
 	_ = max
 	_ = min
 }
+
+func foo1(new int) { // MATCH /redefinition of the built-in function new/
+	_ = new
+}
+
+func foo2() (new int) { // MATCH /redefinition of the built-in function new/
+	return
+}
+
+func foo3[new any]() { // MATCH /redefinition of the built-in function new/
+}